Unkind split: TV's George Lopez filed for divorce after his wife Ann gave him her kidney

If she says to you, glancing over her shoulder at the mirror, "Does my bum look big in this?'' and you say, "No, you'd look good in a sack'' and you go out for the evening and all eyes are on her big bum, what then? If, on the other hand, you say, "You look like mutton dressed as lamb'', and she changes to a more becoming outfit, where are you now?

She's hurt by your cruel retort, tact not being your strong point, but in the end, on your evening out, the eyes are only on you, eyeing up how such a jerk has landed such a classy lady.

You've been cruel - to be kind, bless you.

It's an all too-familiar scenario, illustrating that sometimes you have to be cruel to be kind, as in when you ask her, "Am I too hard on the kids?'', and she says, "Yes'', only because she wants you to have a good and give-and-take relationship with the truculent teens who suddenly seem to have taken over your castle.

And only because in the end she loves you and wishes nothing but kindness towards you and expects the same in return.

I mention all of this only because tomorrow is National Kindness Day - just another excuse for the card companies and florists to make money, you say, begging the question: Are you being unkind to struggling retail industries? Actually such purveyors of sentiment and candy-kisses won't cash in on the day for, unlike other national days in honour of Ma, Grandma, and the dog-next-door, tomorrow is just about kindness itself, pure and simple, which prompts me to ask: What is kindness? And, what does it mean to be kind?

Kindness, according to the dictionary, is the act or the state of being kind - marked by goodness and charitable behaviour, mild disposition, pleasantness, tenderness and concern for others. It is known as a virtue, and recognised as a value in many cultures and religions.

Aristotle wrote of it being being "helpfulness towards some one in need, not in return for anything, nor for the advantage of the helper himself, but for that of the person helped", while Friedrich Nietzsche argued that kindness and love are the "most curative herbs and agents in human intercourse".

Tennessee Williams in his great A Streetcar Named Desire talks of being "full o' the milk of human kindness'' and I would venture to say that most, if not all, of Shakespeare's output could be considered a study of human kindness - "that best portion of a good man's life ... his little, nameless, unremembered acts of kindness ... ''(Macbeth) - or the lack thereof.

A psychoanalyst of my acquaintance (don't ask!) tells me that "real kindness changes people in the doing of it, often in unpredictable ways. Real kindness is an exchange with essentially unpredictable consequences''. Better to be the giver than receiver, as some of us may have learnt down the years ... kindness bringing its own reward.

But he also argues that, in a relationship, "real kindness, real fellow-feeling, entails hating and being hated - that is, really feeling available frustrations and through this coming to a more real relationship''. Mmm, not sure about that one, though it probably goes some way into giving us an insight into the dress/bum scenario above. Sometimes kindness is thrown right back in your face. Take the case of American chat-show host George Lopez and his wife Ann. George sued for divorce last year, after 17 years of marriage. Their split came as a shock because Ann had donated one of her kidneys to George, who suffered from a genetic condition that made his own organs deteriorate.

Thanks for the kidney babe, thanks for saving my life - now I want a divorce. Last I heard, as only Americans can do, the good lady is looking for her kidney back.

Most of my life I have experienced little acts of kindness but Ann and the kidney brings to mind last year when I was undergoing open-heart surgery (nothing too serious, TG). Being a certain age, and my first time 'going under', I was petrified: I thought, "this could be it, the end of the road, you read about people going under and never regaining consciousness ...''

The anaesthetist, who is really the key guy in all such matters, sensed my fear (probably helped by the fact I was shouting loudly and basically losing the plot).

It was the first Sunday after my 'life-saving' open-heart surgery and I had just come down from the High Dependency Unit, lying there feeling forlorn, sorry for my state of affairs, if not happy just to be back in the land of the living, when a man appeared at the side of my bed, in civvies, and I took a moment to recognise him.

It was my friend the anaesthetist.

"What has you working on a Sunday,'' I asked.

"No, I don't do Sundays,'' he said. "Was just out for a spin on the bike and thought I'd swing by, and see how you're doing ...''